Caesium fluoride conducts electricity when liquid or dissolved in an ionizing solvent such as water. Solid caesium fluoride, the stable state of the pure compound at standard temperature and pressure, does not conduct electricity.
No, in its pure form hydrogen bromide is composed of diatomic molecules. Though in water it completely dissociates into ions as it is a strong acid as are the other hydrogen halides with the exception of hydrogen fluoride.
No. Hydrogen peroxide is usually dissolved in water to make it more stable. The peroxide you buy at the pharmacy is 3% hydrogen peroxide and 97% water. Pure hydrogen peroxide, which is a dangerously strong oxidizer, can explosively decompose into water and oxygen.
By electrolysis, passing an electric current through the water. Hydrogen and oxygen appear at the two different electrodes, hydrogen at the anode and oxygen at the cathode. The water needs to have some salt dissolved in it as pure water has a high resistance.